The current technique for the propagation of microbial cultures includes admixing appropriate chemicals for a nutrient supply, water, and a support for the culture. Usually the support is the seaweed extract, agar. Agar is used primarily because it exhibits the desirable properties of:
1. WATER RETENTION
2. A FIRM GROWING SURFACE WHEN COOL
3. EASE OF HANDLING WHEN DISSOLVED IN BOILING WATER
4. ALLOWED MOBILITY OF THE NUTRIENT IONS.
Agar also possesses undesirable properties. Agar is an organic compound, more specifically a polysaccharide; because of this it is susceptible to degradation and subsequent digestion by some types of microorganisms. Agar is also not tolerant to the entire range of pH that is sometimes employed in the culturing of microorganisms. Agar has water-retention properties that are of limited duration. In incubated petri dishes agar may dry out in a period of 1 to 2 weeks rendering the colony dormant or dead. In capped test tubes agar may last longer, but it still dries out in a period of several months. Besides the physical and chemical drawbacks associated with the use of agar as a microbial growth medium, there are also economic drawbacks. Agar has increased in price by a factor of 2 to 3 times over the past several years, and supplies seem to fluctuate depending on ocean currents and other harvesting conditions.
Due to the aforementioned drawbacks associated with the use of agar as a microbiological culture support medium, an alternative support medium that exhibits the desired agar characteristics and less of the undesired characteristics would be very valuable.